5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

Production Of Graphene Reinforced Nylon 6.6 Nanofibers By Electrospun Method

Agarwal, Greiner [1] emphasized importance of electrospinning technique for the modern life requirements. They investigated the preparation schemes, analyzed properties of the nanofibers in terms of electrospinning parameters, and evaluated the potential applications. They stated that electrospinning would be a pioneer especially in the field of life science (tissue engineering, drug delivery, wound healing, etc.), magnetic, optical, sensoric and micrometer-sized electronic devices. Zhang and Yu [2] put a special importance to the fabrication and applications of electrospinning with nanoparticles (NPs) and reviewed recent advances and future prospects. They focused on two main production strategies. One was preparing the NPs–electrospun fibers during electrospinning, and the other was preparing the NPs–electrospun fibers after electrospinning. Although the both methods were facile, cost effective, and flexible methods, they had several drawbacks. However, authors stressed that manufacturing NPs with fibers by electrospinning technique would present a new area for production of multifunctional materials in the future. They would be used in place of supercapacitors, batteries, and dye-sensitized solar cells owing to their large accessible surface area and relatively high electrical conductivity. Eatemadi, Daraee [3] worked on electrospun nanofibers and their various applications in biotechnology. They focus on tissue engineering, delivery, and cancer therapy. The nanofiber scaffolds produced by electrospinning were used for tissue engineering, organ regeneration, and delivery of nucleic acids. Electrospun nanofibers were employed as wound dressings to protect a wound against external effects. The paramount role of graphene-based embedded in polymer matrix via electrospinning is to enhance the mechanical properties of the polymeric nanofibers. Wang et al.,[4], examined PAN/GO composite nanofibers with lateral force microscopy and force-distance curves, in order to assess the surface properties like friction force and elasticity. The experiment results indicated that, with increasing GO concentrations, both the surface friction force and adhesive force increased. The electrospun membrane indicated that 55% of the tensile strength increased, a 127% rise in toughness, and the achievement of maximum strength reinforcement efficiency was reported at 1.5 wt. % GO loading. An even smaller loading of GO (0.02%) in PVA diluted aqueous solution was able to produce elevation of tensile strength of electrospun nanofibers by 42 times [5]. The production of weight ratios of 1, 3 and 5 % multi-walled carbon nanotube reinforced / unreinforced polyvinyl alcohol (PVA) nanofiber mats was carried out by electrospinning method. Tensile strength, modulus of elasticity and elongation amounts were investigated by tensile tests under static loading with / without reinforced nanofiber mats. % 1 MWCNT reinforced PVA nanofiber mats, ç, E and toughness increased by 50, 88 and 12 %, respectively, when compared with PVA nanofiber mats [6]. Nylon 6.6 (PA 6.6) nanomats and PA 6.6 nanofibers containing 1, 3 and 5 wt. % graphene were produced by electro-spinning method. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the nanofibers. Furthermore, changes in the surface morphology of the nanomats were investigated by scanning electron microscopy (SEM) (Fig. 1). While the diameters of the nanofibers ranging between 212-415 nm, the diameter of 5% wt. graphene introduced PVA nanomats were measured as 112-178 nm (Table 1.). Fig. 1: 50 KX magnification of SEM images of nanofibers; a) PA, b) 1%G+PA, c) 3%G+PA and d) 5%G+PA Table 1. Average diameters of nanofibers Nanomat Properties of Nanofiber Average results PA Nylon 6.6 nanofiber 212-415 nm 1%G+PA 1 wt. % content of graphene reinforced nylon 6.6 nanofiber 185-327 nm 3%G+PA 3 wt. % content of graphene reinforced nylon 6.6 nanofiber 152-264 nm 5%G+PA 5 wt. % content of graphene reinforced nylon 6.6 nanofiber 112-178 nm The DSC analysis of electrospun nylon 6.6 nanofibers was as shown in Fig.2. According to the following graph, when graphene and nylon are compared with each other it was observed that an increase in the melting enthalpy of the nanofibers is observed. Graphene’s acted as physical barriers due to their large surface area and the intercalation of crystal structures in the polymer, which increased the melting temperature of the crystalline phase in the pure polymer. The increase for graphene resulted in agglomeration among the fibers, and this result in turn led to a decrease in the melting enthalpy. Fig. 2: DSC curves of graphene/nylon 6.6 nanofibers Keywords: DSC, Electrospinning, Graphene, Nylon 6.6 Nanofibers, SEM Acknowledgments This work was supported by The Scientific and Technological Research Council of Turkey (Tubitak project no: 215M777). References: [1] Agarwal S, Greiner A, Wendorff JH. Functional materials by electrospinning of polymers. Progress in Polymer Science. 2013;38(6):963-91. [2] Zhang C-L, Yu S-H. Nanoparticles meet electrospinning: recent advances and future prospects. Chemical Society Reviews. 2014;43(13):4423-48. [3] Eatemadi A, Daraee H, Zarghami N, Melat Yar H, Akbarzadeh A. Nanofiber: synthesis and biomedical applications. Artificial cells, nanomedicine, and biotechnology. 2016;44(1):111-21. [4] Wang Y, Tang JG, Xie SQ, Liu JX, Xin ZC, Liu XL, et al. Leveling graphene sheets through electrospinning and their conductivity. Rsc Adv. 2015;5(52):42174-7. [5] Wang C, Li YD, Ding GQ, Xie XM, Jiang MH. Preparation and Characterization of Graphene Oxide/Poly(vinyl alcohol) Composite Nanofibers via Electrospinning. J Appl Polym Sci. 2013;127(4):3026-32. [6] Ekrem M. Mechanical Properties of MWCNT Reinforced Polyvinyl Alcohol Nanofiber Mats by Electrospinnig Method. El-Cezerî Journal of Science and Engineering. 2017;4(2):190-200.
Mehmet Açık, Mürsel Ekrem, Ahmet Avcı